Method of and means for transmitting pictures



March 10,1925.

' M. FERREE ET AL METHOD OF AND MEANS FOR TRANSMITTING PICTURES Filed Dec. 3, 1924 7 SheetsI-Shet 1 1924 '7 Sheets-Sheet 2 Irweniors:

Filed Dec. 3,

M FERREE ET AL METHOD OF AND MEANS FOR TRANSMITTING PICTURES March 10, 1925.

March 0. 1925.

M. FERREE ET AL METHOD OF AND MEANS FOR TRANSMITTING PICTURES Filed Dec. :5, 1924 7 SheetS-Shet 5 March 10, 1925. 1,529,473

M. FERREE ET AL METHOD OF AND MEANS FOR TRANSMITTING PICTURES Filed Dec. 3, 19 7 Sheets-Sheet 4 gvwemtm;

nag/s March 10, 1925. 1,529,473

M. FERREE ET AL METHOD OF AND MEANS FOR TRANSMITTING PICTURES Filed Dec. 5, 1924 7 Sheets-Sheet 5 March 10, 1925. 1,529,473

M. FERREE ET AL IIITHQD OF AND MEANS FOR TRANSMITTING PICTURES Filed Dec. 3 1924 7 Sheet-Sheet 6 M. FERREE ET AL METHOD OF AND MEANS FOR TRANSMITTING PICTURES March'lO, .1925. 1,529,413

Filed Dec. 3, 1924 '7 Sheets-Sheet 7 avwemtow ia/WW Patented M... 10, 1925.

- UNITED STATES PATENT OFFICE.

mAnvTN ream, on NEW YORK, N. 1, AND .rosnrn ,wrssmn, or CLEVELAND, vorno, AssreNons, BY unsNn AssreNunNrs, 'ro PACIFIC a ArnANrIc rnoros; me, or NEW YORK, N; Y., A CORPORATION or NEW YORK. A

men or AND mNs non. :rnANsmr'nNe morons.

Application Med December 8, 1924. Serial No. 758,648

To all whom it may concern:

Be it known that we, MARVIN FERREE and JosEPH WISSMAR, citizens of the United States, residing at New York city, county 6 and State of New York, and at Cleveland, in the county of Cuyahoga and State' of Ohio, respectively, have invented certain new and useful Improvements in Methods'of and Meansfor Transmitting Pictures, of

10 which the following is a specification.

Our invention relates to a new and improved electro chemical method of trans-- mitting written, printed and pictorial matter in general including photographs, draw- 16- ings, handwriting, fingerprints and the like.

The'method consists generally of transform ing the variations in light in the matter to be transmitted into electrical pulses, and then causing said electrical pulses to reproduce the said variations by the decomposition of a suitable chemical solution. immaterial for the purposes of our invention whether the electrical 'pulses are sent on. a telegraph wire in whichthe return circuit is made through-the earth, or on a telephone wire which ordinarily has a complete metallic circuit, or-whether the electrical pulse or current. is transmitted by the well known methods of wireless telegraphy. One of the objects of our invention is t devise such a method whereby the object to be reproduced can be rapidly and accurately reproducedwith sufiicient' 'clearness and detail over long distances.

Another object of our invention is to '-devise a methodwhereby proper and perfect synchronism can be secured at the sending station and at the receiving station so that the reproduction shallat all times accurately correspond to the transmission.

Another object of our invention is to provide for a method of transforming the picture to be reproduced into a sending plate having properties specially adapted or the particular purposes of this invention.

' Another object of our invention is to reproduce the picture in a special tone or color whereby the said reproduced picture can be It is' re idly and accurately co ied by any suitab e process of photomec anical printing. l 3y picture we generally refer to the ob-. eet to be reproduced and this term includes drawings, handwriting and the like as above adapted for use with telegraph lines arranged on the duplex system so that the sending impulse and the correction im pulse can be simultaneously sent directions along the same line. 7

Other objects of our invention are to devise certain improvements in the mechanism forcarrying out the above method.

Other objects of our invention will be set forth in the following description and drawings which illustrate a preferred embodiment of our system, it being understood that the previous statement of the objects of our invention is intended merelyfor general explanation and not to limit our invention in any manner whatever.

Fig. 1 is a top view of part of the mechanism used for carrying out ourinvention.

Fig. 2 is a front elevation of Fig. 1.

- Fig. 3 is a detail view of the internal mechanism of the electrical governor used for controlling the motors which drive the in opposite transmitting drum and the receiving drum.

Fig. 4 is a side elevation of the governor.

Fig. 5 is a sectional internal view of the governor. i Fig. 6 is a detail sectional view of the clutch used for connecting the drum to the driving wheel of the motor.

Fig. 7 is a sectional view of the needle arm.

Fig. 8 is a sectional view illustrating the relationship between the needle and the sensitized paperupon the receiving drum.

Fig. 9 is a detail view showing part of the correction mechanism for securing perfeet synchronism between the transmitting apparatus and the receiving apparatus.

Fig. 10 .is a detail View showing part of the mechanism for breaking the picture circuit at the time that the correction pulse is received.

Fig. 11 is a sectional view of part of Fig. 10.

ig. 12 is a diagrammatic view showing part of the electrical connections.

Fig. 13 is a diagrammatic view illustrating the connection of either the receiving device or the transmitting device to a standard duplex line. a

Fig. 14 is a diagrammatic view showing the electrical connections between our receiving or transmitting mechanism and the mechanism ordinarily found in a duplex telegraph oflice.

Fig. 15 diagrammatically illustrates the connections whereby the apparatus may be employed either with a duplex system or with an ordinary single telegraph wire.

Fi 16 illustrates the connections for the circuit of the motors used for-synchronously driving the transmitting drum and the receiving drum.

Fig. 17 is a'diagrammatic view of the sending plate.

The picture to be reproduced is first placed in front of an ordinary camera so that a negative can be made thereof. This negative' is made upon an ordinary transparent glass plate either wet or dry. Before the negative impression is made, a transparent grating having aseries of parallel opaque lines thereon is placed in the camera before the negative so that the negative image consists of a series of parallel opaque lines of varying width and the continuous tone of the picture to be reproduced is thus duplicated in what may be called broken tone.

The spacing'of the opaque lines may vary and we do not wish to limit ourselves to any particular spacing but we have found that a gratin having sixty-five lines to the inch is satis actory for reproducing ordinary photographs. The width of the said opaque lines may be equal to the distances between them but we do not wish to limit ourselves to an particular tpe of .grating. lVe have ound the use 0 gratings having parallel lines to be far superior to gratings having lines crossing each other for this particular purpose because the points of light in the picture to be reproduced are, according to our invention, spread out only in the vertical direction instead of being spread out both in the vertical and in the horizontal direction. Hence, the transmitting plate which will'be later described does not con-. sist of a series of separated dots of insulating material. Experiments have shown that the improved transmittingplate made according to our process avoids the coarse pattern effect produced when the negative is taken through a grating having cross lines. We

refer to have the opaque lines of the gratmg held horizontally when the negative is taken. The negative thus produced is now used for making an enlarged positive by means of an ordinary camera. We prefer to make this positive twice as large as the negative of the original picture. This enlargement enables asuperior transmitting plate to be reproduced. The enlarged positive thus produced is now printed upon a thin plate made of copper or other suitable bendable metal by means of an ordinary printing frame. This metal plate which may be called the transmitting plate is coated with a sensitive coating comprising fish glue, ammonium bichromate and white of eggs. This coating is made of sixteen ounces of fish glue, one ounce of ammonium bichromate, six egg whites and thirty'four ounces of water. These ingredients are thoroughly mixed and they are spread upon the highly polished surface of the copper plate. This coating is then dried, in which condition it is not very sensitive to daylight but is sufficiently sensitive to the powerful are light I 'used for printing thereon from the enlarged positive. After the copper plate has been exposed, it is washed in cold water until the portions of the coating which have not been acted upon by the light are washed away and the plate is then dipped in aniline dye which is absorbed by the remaining gelatine so as to furnish a reproduction of the image to see if the photographic work has been properly done. The plate is then washed to remove any surplus dye and it is then baked over suitable'fiame or the like until the-adhering coating has been transformed into a hard enamel-like material. After the enamel has been formed, the plate is cleaned by rubbing it with a mixture of salt (Na Cl) and dilute acetic acid as this eats away any of the gelatine which does not correspond to the image so as to produce clean bright copper lines between parallel lines of enamel of varying width without etching the plate. This plate is now bent so that it can be placed upon the transmitting drum and the lines of copper are parallel to the axisof the drum.

The transmitting apparatus and the receiving apparatus are duplicates of each other but for convenience we will call the apparatus shown in Fig; 1 the transmitting apparatus. The transmitting drum 1 is mounted upon the shaft 2. The shaft 2 is mounted in the bearings 3 and 4., The drum 1 has a recessed tip and this is engaged by the pointed member 5. The member 5 is mounted at the end of the pivoted bearing 6 which is pivoted at 7 to a bracket mounted on base 8 of the machine. The pivoted bearing 6 is held in the upright position by means of a pin 9 having a head 10. As shown in Fig. 1, the shaft 2 is driven by the shaft 10 of the electric motor M by means of motor M has a, worm 11 and this actuates a worm wheel 12 upon the lateral shaft 14. The lateral shaft 14 has a worm which engages the worm wheel 15 which is mounted loosely upon the shaft 2. The shaft 2 has a holding member 16 keyed thereto and the ordinary compression spring 17 is mounted upon the shaft 2 with one end of the said spring 17 abutting the member 16. The compression spring 17 urges the worm wheel 15 to the left, so as to compress the felt disc 18 which is in contact with the driving member 19 which is connected to the shaft 2 by the set screw 20. Hence, the motor M drives the shaft 2 through a friction clutch which can be caused .to' slip, whenever re-' quired so that the shaft 2 can be held against revolution while the motor M is allowed to continuously revolve.

As clearly shown in Fig. 1 and Fig. 2, the shaft 2 has a gear 21 and this is in mesh with a second gear 22 which is mounted upon the secondary shaft 23. The secondary shaft 23 \is held betweentwopointed members 24 and 25 mounted in bearings 26 and 27. These bearings 26 and 27 are provided with adjustable means 28 for enabling them to be held in various positions. Bearings of this type are in themselves well known and require no further description. The shaft 23 is externally threaded at 29 so that when it is revolved the needle arm is moved from leftto right. The needle arm 30 is slidably mounted upon the arm 31 which is mounted in adjustablebearings 32 and 33 of the type needle arm 30 is provided with an internally threaded member 34 which co-operates with the threading 29 of the shaft 23. The internally threaded member 34 is connected to the arm 30 by means of springs 35 whose position can be controlled by means of the screw 36. The needle carrier comprises a metal arm 37 pivoted to the needle arm 30 at 28. The position of the arm 37 can be regulated by means of the screw 39. An arm 40 made of fibre or other insulating material is connected to the metal arm 37 by means of an ordinary bolt 41.

The needle N is mounted at the end of an angular blade spring 42 and this blade springis mounted at the end of a sleeve .43 which is slidably mounted within an outer sleeve 44 suitably connected to the fibre arm 40. The head to which the blade spring 42 is connected is held in the inner sleeve 43 by means of the set screw 45 and the position of the inner sleeve 43 in the outer sleeve 44 can be regulated by means of the set screw 47.

T he transmitting needle N is preferably made of hard steel while the receiving needle N is preferably made of an alloy of platinum and iridium so as to be unaffected by the chemical action later described.

It is highly important that each of the needles N should be held in position with the proper de ree of pressure against the transmitting plate, or against the paper on which the picture is to be reproduced. The transmitting needle N must bear firmly against the transmitting plate so as to have efficient electrical contact with the naked metallic portions of the copper plate and it must not hear so firmly against the transmitting plate as to cause scratching of the enamel.

\Ve have found that the angular blade spring 42, together with the ad ustment of the. head 45 and the inner sleeve 43 before mentioned is highly efficient in producing the proper degree'of pressure.

As previously stated the metal plate having the enameled image thereon is placed upon the drum 1 with the lines of the image parallel to the axis of the drum.

Hence, as the transmitting drum 1 is revolved, the needle N is slowly moved to the right so that it crosses the relatively perpendicular lines of enamel which are of varying width.

Hence. by means of connections to be later described, the needle N is caused to close an electrical circuit when it is in contact with the naked copper of the plate and the said circuit is broken when the transmitting needle N is in contact with an enamelled portion of the plate so that a series of electrical pulses are produced. These electrical pulses I A vary in duration in proportion to the tones before mentioned. As shown in Fig. 7, the

of the original picture.

While the transmitting drum is revolving, a duplicate drum is being revolved at the receiving station save that the duplicate drum has one-half of the diameter of the transmitting drum. The transmitting drum and the receiving drum are revolved in synehronism. The needle at the receiving drum is actuated by a mechanism similar to that before described. but the worm or threading for longitudinally actuating the needle arm has a pitch which is one half the pitch of the threading 29.

The arrangement of the parts at the receiving drum is depicted in Fig. 8. The receiving drum 49 has an absorbent pad 50 suitably held upon the surface thereof. This pad 50 is saturated with a solution whose electrical decomposition produces a color effect. This solution is preferably a starch or dextrine solution in water which contains dissolved otassium iodide and dissolved potassium romide. The effect of the addition of the postassium bromide is to secure markings of a brownish tone upon the recording paper 51 with which the recording or receiving needle N contacts. This receiving paper 51 is saturated with the solution before mentioned. However,

experience has shown that the absorbent 1 &

pad 50 which is made of a pure unsized paper consisting practically of pure cellulose is highly important because otherwise the receiv ng paper 51 dries so quickly that long pictures cannot be efiiciently received. By reason of the use of the absorbent pad 50, the absorbent receiving paper 51 can be kept ina suitably moist condition for many hours, it necessary. By reason of the-electrical connections, the receiving needle N forms a positive or duplicate of the original picture in broken tone, but this broken tone is imperceptible and is not visible to the nakedeye because the picture formed upon the receiving drum is one half the size of the picture on the transmitting plate and in addition the lines formed upon the rev ceiving paper 51 spread out slightly so as to practically neutralize the broken tone efi'ect. Hence, the picture formed upon the receiving paper 51 can be directly copied by the ordinary processes of photomechanical printing. The electrical connections between the drums for securing the reproduced picture are diagrammatically illlustrated in Fig. 12. The battery 52 which enables the instrument to act both for transmitting and receiving is of the ordinary dry cell type and-has sutficient individual cells to give it a maximum voltage of twelve volts. The full voltage of twelve volts is used on the transmitting plate and the tap connection 53 enables a smaller voltage, preferably not greater thanv two volts, to be used upon the receiving paper. By reason of the high resistance employed, the current for receiving does not exceed about three-tenths of a milliampere. In the view shown in Fig. 12 the plus side of the battery 52 is assumed to be at the left-hand side thereof and this plus side is connected to the needle N when it is used for transmitting. The plus terminal 54 of the battery 52 is connected to one of the terminals 55 of a twelve-point switch diagrammatically illustrated at the lower left-hand corner of F ig. 12. In the position of the parts shown in Fig. 12 the switch is supposed to be in the neutral or zero position in which the apparatus is not working. The said switch has additional terminals 56, 57, 58, 59, 60, 61 and 62 and has four switch levers 63. 64, 65 and 66. The four switch levers 63, 64, 65 and 66 are caused to move in unison by any suitable connections which are not illustrated in the drawings, because multiple contact switches of this type are in themselves old and well known.

When the switch levers are moved to the lower position so that they contact with the lower terminals 55, 57, 60 and 62, the device is operative for transmitting purposes. The,

lead 67 which is connected to the terminal 55 when the switch is in the lower position is connected to the jack J which serves for pluggin in a, transmitting polarized relay of any s uitable type. The ordinary Wheatstone polarized relay-has been found suitable for this purpose. The marking coil 69 of relay R is connected through jack J to the jack J, by means of suitable plugs, so.

that said coil 69 is in series with the current passing to needle N. The current passes through entering lead 68, then through coil 69 and out through lead 70 to the other terminal of jack J After passing through the marking -coil 69 the current then passes from the needle N to the drum 1 whenever the needle N contacts with the naked or conducting portion of the transmitting plate. The current then passes to the shactt 2 of the drum 1 and to the cam device 71 shown in detail in Fig. 10. The cam 71 is provided with two adjustable discs 72 and 73 which can be circumferentially adjusted so as to leave a space 74 which can be varied in size. A spring 75 mounted upon the insulated support 7 6 contacts with the edges of the metal discs 72 and 73 so as to tap the current therefrom. However, the circuit is broken when the end of the spring 75 is in the space 74. The spring 7 5 is connected to the lead 77 which is connected to the switch'lever 65. Since the four switch levers of the switch are supposed to be in their lower position, the current then passes to the lower terminal 61) and through the lead 78 into the transmitting meter 79 which indicates the strength of the current. The current then passes through the lead 80 into the adjustable re-' sistance 81 and then through the lead 82 to the lower terminal 57. The current then passes through the switch lever 64: to the lead 83 to the switch lever 66, then to the lower terminal 62 and then through the lead- 84: to the negative side of the battery through terminal 52.

The machine is preferably mounted upon an insulating base and the'parts are so arranged and constructed in the manner well known to the art so that the circuit above mentioned is complet .l as previously described.

- Whenever the needle. N contacts with a naked portion of the transmitting plate T. a current pulse is sent to the marking coil 69 of the transmitting relay R, as shown in Fig. 15. This impulse actuates the armature A of the relay to be connected with the marking terminal 85, closing a circuit which leads either directly to the telegraph line or to the connections of the telegraph oflice.

It has been found by experience that the ordinary very slight magnetic bias found in the ordinary polarized relay is not sufficient to move the armature A away from the marking terminal with sufficient accuracy and synchronism of movement for pulses of various degrees of strength and ence the spacing coil 86 of the relay is proconnected to the spacing coil 86 through the variable resistance 88.' The circult is completed through a jack 89 which is connected to the plus terminal 90 and to the minus terminal 91 shown in Fig. 12 so that the circuit of the biasing current is completed through the meter 92 which shows the strength of the biasing current.

W'e have found that the control of the biasing current also controls the tone of the reproduced picture. For example, when the meter 79 shows that the local transmitting current is 80 milliamperes, then meter 92 will indicate that about 7 milliamperes are being used in the biasing current. If the biasing current is made much greater than 7 milliamperes, the relay does not respond to the short faint impulses corresponding to the light and fine tones of the picture. On the other hand, if'the biasing current is made too weak in proportion to the local transmitting current then the armature A will tend to stay'too long on the marking side thus resulting in a darker picture.

The armature A is connected to the terminal 93 of the relay R and this is connected by means of the leads 94 and 95 tothe switch lever 96. In the position of the parts shown in Fig. 15 the switch 96 is connected to the ground G through the resistance unit 97. The marking terminal 85 is connected to the lead 98 and this is connected through the closed jack 99 to the closed telegraph key 100 and to the leg L. The leg L may go to any ordinary telegraph ofiiceto be connected to the duplex set in any suitable manner so that the movement of the armature A controls the transmission of the duplex, which in turn controls the line current which may be the ordinary current of 160 volts. If it is desired to interrupt the sending of the picture to transmit a message by means of the key 100, then the switch lever 101 is moved from the position shown in Fig. 15 until the lower end thereof contacts with the terminal 201. This shunts the contact points of relay R so that the key may be used in the ordinary man-' ner.

In order to use the instrument for receiving purposes, the switch levers 63, 6 1, and 66 are moved to the upper position so that they contact with the terminals 56, 58. 59 and 61.

At the same time, the tap terminal 53 is connected to the battery 52 intermediate the ends thereof so as to tap oil a receiving voltage of about two volts.

The local receiving current passes through the tap terminal 53 to thelead 102, to the terminal 56, thrpu h the switch lever 63, through'the lead 6 and through the 'ack J which, as before stated, is connecte to thetelegraph. line through a receiving relay to the needle N through the shaft 2 and tl18'C2tIl1'71, through the lead 77 through the switch lever 65 to the terminal 59, through the lead 103 to the variable resistance 104 and through 13118118341 105 to the receiving meter 106.

The current passes through the receiving meter 106 and then through the lead 107 to the terminal 58 through the switch lever 64 through the lead 83 to the switch lever 66; then to the terminal 61 and through the lead 84 to the negative side of the battery 52. The pulse passing over the telegraph line is received by the duplex instrument in the receiving telegraph oflice and then repeated into or through the receiving leg L of the said line. This receiving leg L is connected to the marking coil 108 of the receiving relay R and the leg or local circuit current is regulated in the well known manner by resistance 112 so that it may properly operate the receiving relay R.

The line current then passes through the closed jack 109, through the lead 110 to the switch 111 and then to the ground through the resistance unit 112. This completes the incoming circuit. The marking coil 108 actuates the armature A of the relay R. The marking impulse moves the armature A to the right so that it is connected with the terminal 114. The armature A is connected to the terminal 115 so that the jack 116 is connected on one side to the armature and on the other side to the marking point of the relay R. The jack 116 has its terminals connected to the terminals of the jack J.

Hence, whenever the armature A moves to the marking side, this completes the circuit of the local receiving current so as to form a marking upon the receiving paper 51.

In order to synchronize the movement of the receiving and transmitting drums, means are provided for securing the uniform revolution of the motor M and then a correction impulse is sent over the line for each revolution of the drum so as to cause the receiving and transmitting {drums to revolve in unison. Each motor is provided with an electrical governer G which maybe of any suitable type. The type of the governor which we prefer to employ is shown in detail in Figs.- 3, 4 and 5. The governor G comprises two metal rings 117 and 118 separatedby an intermediate ring 119 made of fibre or other suitable insulating material. The metal rings 117 and 118 co-operate with brushes 120 and 121 which are connected to the leads 122 and 123. ,As shown in Fig. 16, the motor power line is connected to the terminals 124 and 125. The current passes through the switch 126 to the terminal 123,-

then to the ring 118 and then into the con- -tact spring 127. The contact spring 127 is nected by means of the conducting member 132 to the other ring 117. The current then asses to the terminal 122 through the rush 121 to the motor connection 133, then through the motor out to the other motor connection 134 and to the power lead 124.

When the speed of the motor exceeds a certain limit, the centrifugal force moves the spring 127 away from the contact 128 so as to break the current. In order to minimize any substantial irregularity in the revolution of the motor a shunt adjustable resistance 135 is provided which is thrown into series with the line only when the governor spring 127 is opened. This is obvious from the connections shown in Fig. 16.

The adjustable resistance 135 preferably has a resistance which is preferably much higher than the internal resistance of the motor M.

' In order to minimize sparking, a second adjustable resistance 136 is provided which preferably has the same value as the adjustable resistance 135 and the adjacent ends of the resistances 135 and 136 are connected to the terminals of a condenser C.

As previously stated, the shaft 2 is revolved by the motor M by means of a friction clutch arrangement so that the movement of the shaft 2 can be stopped whenever desired while the motor M is allowed to continue revolving.

The shaft 2 has a stop disc 136 mounted thereon, and as shown inFig. 9 this stop disc has a notch formed, upon the circumference thereofso as to produce a lug or shoulder which can be engaged by the detent 137. This detent 137 forms the armature of the electron'lagnet 138. The detent'137 is pivoted at 139 to the frame of the magnet and it is urged into the holding position by.

the tension spring 140. Hence. the detent 137 engages the disc 136 at each revolution thereof so as to hold the said discf and the shaft 2 stationary until the detent 137 is re-. leased by the energizing of the electromagnet 138.

The correction impulse for energizing .the magnet 138 is controlled by means of a correction disc 141 shown in Fig. 1, Fig. 2'and Fig. 12. This correction disc 141 is made of fibre or 'other suitable insulating material and it is provided witha metal segment Whichis adapted to contact with the brushes 142 and 143 for a short period during each revolution of the shaft 2. When the detent 137 engages the disc 136 to stop the revolution of the shaft 2 at the sending end, then the brushes 142 and 143 at the sending station are connected by the metal segment on the correction disc 141 so as to receive a correction impulse from the receiving station.

The parts are so adjusted that the drum at the sending station is a trifle faster than the drum at the receiving station so that the drum at the sending station is first stopped until it receives a pulse from the receiving station. Hence, the movement of the drum at the receiving station is continuous and a correction impulse is sent from the receiving station to the sending station during each revolution of the said drums, so that they start eachnew revolution in perfect synchronism. This correction pulse is sent to the sending station at a period corresponding to the time when the adjacent ends of the metal transmitting plate are being passed over by the needle N. If the picture is being sent over a duplex, which would ordinarily .be done, then the same wire can be utilized a single line then the receiving drum would v run slightly faster than the sending drum and the correction pulse would be sent at each revolution by the sending drum which would now be continuously revolved, to the receiving drum which would then be stopped at each revolution thereof.

However, if desired, the sending machine could be used even with a duplex for sending the correction impulse, if it is desired to use the sending machine on a number of lines to transmit the picture simultaneously to a number of receiving stations. The local current for the correction pulse is secured from an ordinary -volt dynamo D. one end of which is grounded by lead G. The positive and ungrounded terminal of the dynamo I is connected by means of'leads D and 144- to one terminal of the magnet 138 through the coil of the said magnet to the brush 143 through the metal segment on the correction disc 141 to the brush 142 and then through the lead 145 to the jack 146 where the relay leading to the line is plugged in. The ground connection for the jack 1.46 is for the purpose of completing the circuit. of the dynamo D.

If weassume that the relay 1t shown in Fig. 15 is being used as a transmission re lay on a duplex. then the correction impulse is received through the relay R. The jack 146 shown in Fig. 12 is then plugged into the jack 147 shown in Fig. 15. The correction pulse which has been sent through the line from the receiving machine. by the arrangement of the parts previously described enters through the line L and passes through the marking coil 108 so that. the armature A is moved to the right as previously mentioned thus completing the local correction circuit since the jack 147 is connected in series to'the connections144 and 115 which have been previously described.

When the local correction circuit has thus been closed, the detent 137 is moved away from the disc 136 and this permits the sending drum to again turn.

In order to provide a bias for the relay R the spacing coil 148 is provided with a bias current through a 12-volt battery 149, the adjustable resistance 150 and the closed jack 151.

At the time that the correction pulse .is being sent, the spring is in the space 71 so that the local picture circuit is broken.

For convenience the sheet of moistened paper 51 will be called sensitized paper. by which term we include a paper moistened with any solution adapted to be decomposed by the passage of a current so as to produce a color effect. 1

The power circuit of the motor M is controlled by an ordinary switch 126.

As shown in Fig. 15,'the marking coil 69 has its ends connected to the terminals of two jacks J and 146. and the marking coil 108 has its ends similarly connected to the terminals of jacks 116 and 147. If the transmission is not along a duplex. but is along a single line then the jacks J and J have their terminals connected, and the jacks 146 and 146 also have their terminals connected. The picture pulse is then sent through jacks J and J and the correction pulse is sent through jacks 146 and 146', at the time when the picture pulses are interrupted. in the mannerbefore stated. The jack 146 has one of its terminals grounded.

Figs. 13 and 14 diagrammatically illustrate the switches for the leg connections of the receiving and transmitting device of a standard duplex system. The current is provided by a dynamo 212 having a switch 205 and a resistance unit 202. In Fig. 1-1. the leads 210 and 211 are connected to the 1.10- volt source of duplex current, and the leads 208 and 209 are connected to the telegraph oiticc. The usual switches 206 and 207 and the usual resistance units 203 and 204, are provided.

'0 have described a preferred embodiment of our invention. but it is clear that numerous changes and omissions could be made without departing from its spirit? and we do not wish to be limited to the details before specified.

lVe claim 1. In an apparatus for transmitting pictures by electrical pulses. the subcombination of a transmitting drum having a transmitting broken-tone plate connected thereto, a receiving drum having a sheet of sensitized paper impregnated with an electrolytc. solution connected thereto, a transmitting needle asociated with said transmitting drum and a receiving needle associated with said receiving drum and means adapted to cause a relative and substantially synchronous movement betweeneach said drum andits needle, each said drum having a source of electric current connected thereto and also to the needle associated therewith, the said receiving drum having a diameter suificientlv smaller than that of the said transmitting drum to cause the markings formed on said sensitized paper by the electrolytic dG'IOIIlPOSliIlOIl of said solution, to spread out so as to produce a substantially continuous reproduction thereon, whereby the said reproduction can be directly copied phot omechanically.

An apparatus according to claim 1. in which said broken tone plate is formed by separated and substantially parallel lines of varying width.

3. In an apparatus for transmitting pictures by electrical impulses, the subcombination of a revoluble member adapted to support a transmitting plate or the like, means adapted to revolve said drum, a needle associated with said drum, means adapted to cause a relative movement between said needle and said revoluble member independent of the revolution of said member, a source of current one terminal of which is connected to said needle and the other terminal of which is connected to said revoluble member, the circuit of said local source of current including the marking coil of a polarized relay, electromagnetic means for controlling the magnetic bias of said relay and a telegraph line whose circuit is controlled by the movement of the armature of said relay.

4;. An apparatus according to claim 3 in which said electromagnetic means comprise a spacing coil. and means adapted to send a bias current through said spacing coil.

5. In an apparatus for transmitting pictures bv electrical pulses. the subcombination of a drum mounted on a revoluble shaft. a correction disc mounted upon said shaft, circuit control means mounted on said shaft. a needle associated with said drum, means adapted to cause a relative movement between said needle and drum. a first local source of current adapted to be conuected to said needle and drum. a polarized relay having a nulrking coil forming part of the circuit of said first local source. a sec-- ond source of current having its circuit con trolled by said correction disc, the circuit of said se-r'ond source of current including said marking coil, said control means be ing adapted to interrupt the circuit of said first local source when said correction disc causes the circuit of said second source of current to be closed.

6. An apparatus according to claim 5 including a tap for said first local source of current, two meters, and a multiple contact switch, the movement of said switch in opposite directions being adapted to send the full current from said first local source through one of said meters and the said circuit of the needle and drum, the movement of said switch in the other direction being adapted to send the weaker current from said tap through the other of said meters and said circuit of the needle and drum. '7. In an apparatus for sending pictures by a series of electrical pulses, the subcombination of a drum 1 mounted on a shaft 2, a needle N adapted to be moved by the actuation of the shaft 2, means' adapted to drive said shaft 2 and to permit said shaft 2 to remain stationary, a battery 52, a marking coil of a polarized relay, connections intermediate one end-of said marking coil and one of the terminals of battery 52, connections intermediate the other end of said marking coil and the needle N, the said shaft 2' being in electrical communication with said drum 1, a correction disc 141 mounted on said shaft 2 and made of insulating material and having a metal segment, a stop disc 136 mounted on shaft 2, electromagnetic means adapted to control the movement of said stopdisc 136, a cam 71 having a conducting surface provided with a gap therein, a spring 75 adapted to bear against the surface of said cam 71 and to conduct current therefrom save when the end of said spring is adjacent said gap, said spring being connected to the other terminal of said battery 52, a dynamo D, one terminal of said dynamo being connected to said electro-magnet-ic means and then through said electro-magnetic means to a brush 143 adapted to bear against the correction disc 141, a second brush 142 adapted to contact with the metal segment on correction disc 141 when it is in contact with said brush 143, said brush 143 being connected through said marking coil to a connection with the other terminal of said dynamo, the said brushes 142 and 143 being adapted to contact with said metal segment.

8. An apparatus according to claim 7 in i which the spacing coil of said relay is c011- neoted to a resistance and a second battery.

9. In an apparatus for transmitting pictures by a series of electrical pulses, the subcombination of the multiple contact switch having terminals 55 and 56 associated with an armature 63, terminals 57 and 58 associated with an armature 64, terminals 62 and 61 associated with an armature 66, terminals 60 and 59 associated with an armature 65; said four armatures being adapted for simultaneous movement, each said armature being adapted to occupy a position free from contact with its respective'terminals and to occupy positions in which contact with either of its-respective terminals, a

battery 52 having a tap 53, one terminal of said battery being connected to the terminal 55, the other terminal of said batterybein connected to'the terminals 62 and 61, a jac 'J having its ends respectively connected to the armature 63 and to a needle N associated with a drum 1 mounted on-a revoluble shaft 2, means adapted to revolve said shaft 2, a

correction disc 141 and a stop disc 136 and a. cam 71 mounted on said shaft 2, said cam on correction disc 141, and a second brush 142 associated with said brush 143, said brush 143 being connected to one terminal of a'jack 146. the other terminal of said jack 146 being grounded, the said marking coil also having its ends connected to said jack 146.

10. In an apparatus for transmitting pictures by a series of electrical pulses, the subcombination of a transmitting drum adapted to have a broken tone plate connected thereto, a transmitting stylus associated with said transmitting drum, a receiving drum adapted to'have a sheet of sensitized paper impregnated with an electrolytic solution connected thereto, a receiving stylus associated with said receiving drum, each said drum having a motor connected thereto, each said drum and its associated stylus being connected to the terminals of a source of current of relatively low voltage, electromagnetic means adapted to control the revolution of one of said drums, an independent source of current of relatively high voltage adapted to energize said electromagnetic means, a movable member actuated simultaneously with the other of said drums and adapted to control the circuit of said independentsource of current to cause it to intermittently energize said electromagnetic means, and means adapted to interrupt the said low voltage supply of current when said electromagnetic means are operated.

11,. An apparatus according to claim 10 in which said movable member operates to cause said independent source of current to energize said electromagnetic means during the interval when .said transmitting stylus is passing between the separated edges of the broken tone plate.

12. In the art of transmitting pictures by a series of electric pulses, those steps in the art which consist in producing a series of electric pulses corresponding to the successive small areas of a broken tone plate of the picture to be transmitted, and then forming a reproduction of said broken tone plate b causing each said pulse to produce a sm 1' ciently enlarged with respect to the spaces '1 between the corresponding original small areas to form a reproduction in substantially continuous tone, which can be directly copied by photo-mechanical methods. In testimony whereof we hereunto aflix our signatures.

MARVIN FERREE. JOSEPH 'WISSMAR. 

